Interesting buzz/hum on Fender Jazz Deluxe... Ideas?

[Hubes]

Hey guys, I'm a lurker around here, usually browsing around the classifieds, but I'm hoping someone can help diagnose a problem I'm having with a bass I recently picked up. It would save me a long drive to visit a repair shop!

So, searching the forums I've noticed several reports of a bad buzz/hum coming from their Fender Deluxe Jazzes, but nothing quite the same as mine.

Anyway, I recently acquired a 2010 MIM Fender Jazz Deluxe bass at a killer price with a slight catch - the old Noiseless bridge pickup had died on the last owner and was replaced with a Duncan.

The bass came with a bit of a buzz issue, which seems to be greatly influenced by the position of the eq/pan knobs. The problem only is audible at volumes above ~50-75%, and touching strings/pole pieces/bridge does not help. The noise persists on several amps, as well as DI'd in to a PA system.

Here's a quick qualitative summary of how the noise is affected:

*All eq knobs flat, volume maxed, bridge/neck pickups 50/50, there is a significant buzz. The rest of this list will assume all knobs in this state except for the listed change:

*Roll treble down: Noise moderately reduced
*Roll treble up: Noise gets worse
*Roll bass up/down: No audible effect
*Roll mids up: Noise GREATLY reduced
*Roll mids down: Noise moderately worsens
*Pan to bridge (non-Noiseless) pickup: Noise gets awful
*Pan to stock neck pickup: Noise reduced, but not as much as boosting mids

If I boost my mids, cut treble, and pan 100% to neck pickup, the noise is inaudible.

Anybody hear of an issue like this? Is this likely a grounding or shielding problem, or something in the preamp or wiring or what? Any help you guys can provide would be greatly appreciated!

[SGD Lutherie]

Is the replacement pickup a single coil?

[Hubes]

It is, so some hum is definitely expected from that pickup. But the hum is only slightly diminished when panning to the stock Noiseless pickup. The Noiseless, if I understand correctly, fits two coils into a single coil housing, thus acting as a humbucker (though it is built to LOOK like a single coil). I've never played a humbucking guitar with as much hum/buzz as this bass produces.

I don't think it's a grounding issue, but perhaps there is a shielding issue? There doesn't appear to be any sort of conductive shielding around the bass. I'm not sure if this would explain why the different EQ knob positions have such a drastic effect on the noise though. Mid and treble knobs both have significant impact on the level of noise, even when the stock Noiseless pickup is 100% rolled.

[SGD Lutherie]

The Fender noiseless is a stacked humbucker.

You can't make a single coil and a hum canceling pickup cancel hum when used together. This is because to make two pickups cancel hum, they both have to pick up hum. So in this case all you are doing is adding hum to the noiseless pickup.

Now there is two kinds of noise you get. Magnetic field noise is the 60Hz stuff that humbuckers get rid of. Then you have electrical field noise, which is that higher pitched buzz. Humbuckers don't get rid of that, so you need shielding.

[Hubes]

I see. I suppose changing the EQ is simply limiting how much of that noise in those frequencies gets through then?

I will try some shielding then, and hopefully around Christmas time I can get my hands on a replacement humbucker!

Thanks for your help!

[Vakmere]

Buy a Ken Smith and you will be buzz free. SGD is correct in what he said.
Single coils are notorious buzzers. Keep the treble on your base turned down and raise the
Treble on your amp if needed.

[arginator]

In this case you could also replace the remaining humbucker and probably still reduce the hum considerably. Those Noiseless Fender Jazz pickups aren't the greatest, sou you may be happier with another Duncan single coil.

[Hubes]

Just so I'm clear in my understanding: Does a guitar necessarily require two humbuckers to effectively cut hum? Or would a lone humbucker (with no other pickup on the guitar) be quiet, but in my case adding a single coil to the mix negates the noise cut?

Noise reduction is something of a priority for me; I'll probably try to grab a new set of buckers sometime soon. I've heard good things about Super Jazzes, perhaps I'll give them a shot!

[Vakmere]

Originally Posted by Hubes

Just so I'm clear in my understanding: Does a guitar necessarily require two humbuckers to effectively cut hum? Or would a lone humbucker (with no other pickup on the guitar) be quiet, but in my case adding a single coil to the mix negates the noise cut?

Noise reduction is something of a priority for me; I'll probably try to grab a new set of buckers sometime soon. I've heard good things about Super Jazzes, perhaps I'll give them a shot!

It's not hum, it's buzz, there's a difference. Yes replace them all with humbuckers.